The electromagnetic spectrum ranges from cosmic rays at one end, to radio waves at the other end. The ultraviolet (UV) region of the electromagnetic spectrum is situated between visible light and x-rays, with the wavelengths of the UV A radiation being shorter and more energetic than violet visible light and the wavelengths of vacuum UV radiation being slightly longer and less energetic than x-rays. The full UV radiation spectrum ranges from wavelengths of about 100 nanometers (nm) to 400 nm and the UV radiation spectrum is usually divided into 4 sections; vacuum UV radiation (also called far or very UV, from 100 nm to about 200 nm), UV C radiation (also called germicide or short-wave UV, from 200 to about 280 nm), UV B radiation (also called mid-wave or medium-wave UV, from 280 nm to about 320 nm), and UV A radiation (also called “poster lamp”, black-light, or long-wave UV, from 320 nm to 400 nm).
UV radiation can be emitted from a variety of sources such as: light emitting diodes (LED's), lasers, electric arcs (especially as in arc welding), xenon bulbs, halogen bulbs, excimer bulbs, and mercury vapor lamps/tubes of low, medium and high pressures. UV C radiation is used extensively for sterilization, purifying, and deodorizing applications in food, air, water, and general surface sterilization processes because the UV C radiation not only deactivates micro-organisms such as: bacteria, molds, spores, fungi, and viruses (by direct irradiation which damages the DNA such that the micro-organisms cannot reproduce), but the UV C radiation also breaks down the chemical bonds of alcohols, pesticides, chloramines, and other contaminants such as NDMA or MTBE. UV B radiation is the agent that causes human skin to “sun-burn” and the UV B radiation is needed to start the suntanning process. The lamps/tubes used in suntanning booths usually emit a combination of UV B and UV A. UV B is also used extensively in various medical treatments-especially for skin diseases. UV A radiation is used for special effect lighting, suntanning, photo-lithography, and photochemistry.
U.S. Pat. No. 6,787,782 teaches a system that uses UV radiation emitting LED's as one source of UV radiation for sterilizing air in a vehicle such as an airplane. Similarly, U.S. Pat. No. 6,233,748 teaches the use of UV radiation emitting LED's in combination with a reactive surface to sterilize air for breathing inside a helmet. However, both of these patents teach that the wavelength is selected at the time of manufacture. Neither of the patents provide any way to vary or transform the radiation from the UV radiation source, which would make the units much more versatile.
U.S. Pat. No. 6,893,610 describes an air purifier apparatus that forces air through two chambers each containing a different kind of low pressure mercury vapor lamp/tube. However, the apparatus requires multiple air chambers and several different varieties of mercury vapor lamps/tubes whereas a simpler apparatus would be more economical and easier to use.
U.S. Pat. No. 6,832,844 describes a way to use a fan to keep a UV radiation lamp/tube at an optimum temperature. However, the patent does not provide any way for the apparatus to emit a transformed UV radiation.
U.S. Pat. No. 5,334,347 teaches a way to overcome the skin effect cooling while simultaneously producing a UV radiation high output lamp/tube. However, the wavelength is selected and fixed at the time of manufacture, and the patent does not teach any way to vary or transform the radiation from the UV radiation source.
U.S. Pat. No. 6,337,483 teaches an apparatus for simultaneously sterilizing air and water with UV C radiation. However, the patent does not teach the use of ozone producing lamps/tubes, nor does it provide any exit port for the apparatus to emit either the primary UV radiation or a transformed radiation as selected by the user. U.S. Pat. No. 1,888,421 describes an apparatus whereby mercury is added to evacuated electrical discharge tubes containing small amounts of various types of inert gases in order to produce the UV radiation emissions characteristic of low pressure mercury vapor. Such UV radiation sources are commonly called either lamps or tubes, with the terms being interchangeable. U.S. Pat. No. 2,135,732 teaches the use of luminescent (phosphorescent or fluorescent) materials coated on the inside of a mercury vapor discharge lamp/tube to produce UV radiation of a different wavelength distribution from that of the low pressure mercury vapor primary UV radiation wavelength distribution. However, in both of these patents, the lamp/tube can only produce a certain fixed wavelength distribution of radiation set at the time of manufacture. Further, the apparatus does not provide any mechanism to vary or transform the radiation while the device is in use.
Generally, to build a fixture designed to selectively emit radiation in more than one wavelength distribution of UV radiation, a separate lamp/tube has been used for each of the desired wavelengths of radiation, UV A, UV B, or UV C radiation. U.S. Pat. No. 5,387,801 and U.S. Pat. No. 5,175,437 each describe an apparatus to select a desired emission wavelength distribution of radiation. However, in both of these patents, the need to use a different UV radiation source for each wavelength distribution of radiation is both expensive and cumbersome, and requires turning each lamp/tube on and off frequently, which is well known to shorten lamp/tube life.
U.S. Pat. No. 4,703,224 teaches coating the inside of a mercury vapor discharge lamp/tube with a mixture of two or more types of phosphors, to emit both UV A radiation and UV B radiation. Similarly, U.S. Pat. No. 4,967,090 and U.S. Pat. No. 5,557,112 each teach the idea of coating the inside of mercury vapor discharge lamps/tubes with two or more different types of phosphors, each in a specific zone or sector on the inside of the cylindrical envelope of the lamp/tube. However, it is well known that phosphors coated on the interior wall of a mercury vapor discharge lamp/tube suffer from exposure to the electric current, mercury atoms and ions, and short-wave UV radiation particularly of wavelengths less than 200 nm, for instance, the 185 nm far UV radiation emission of mercury vapor. U.S. Pat. No. 4,243,090 describes the loss of efficiency and drop in effective light production by phosphors due to these effects. Further, all of these patents teach that the phosphor is inside the lamp/tube where it is exposed to the harsh conditions that exist in that environment, and the wavelength distribution is selected and fixed at the time of manufacture. Further yet, none of these patents teach any way to vary or transform the radiation while the device is in use.
Similarly, U.S. Pat. No. 3,676,728 teaches a lamp/tube capable of producing selectable illumination using a plurality of types of phosphor coated on the interior of a mercury vapor discharge lamp/tube. As in the previous examples, this type of apparatus suffers from the disadvantage of damage to the phosphors that are exposed to the harsh conditions on the inside of a low pressure mercury vapor discharge lamp/tube. In addition, much of the energy of the mercury vapor is wasted because there is no way to direct it toward the desired phosphor in exclusion of phosphors placed at other locations within the lamp/tube.
In U.S. Pat. No. 5,736,744; U.S. Pat. No. 6,670,619; and U.S. Pat. No. 6,911,657, inventor Waluszko describes a wavelength shifting filter as only emitting one particular wavelength distribution of radiation. To select a different wavelength distribution of radiation, a particular flat conversion plate must be physically removed from the apparatus and replaced with a different flat plate. The system is cumbersome to use. In addition, the phosphor on the plates is uniformly distributed-Waluszko does not teach that the phosphors on the plates can be arranged to emit transformed radiation in a pattern, or that portions of the plate can remain phosphor free so that the primary UV radiation can also be transmitted.
U.S. Pat. No. 4,048,537, teaches a protective shield for a UV radiation lamp/tube. Similarly, U.S. Pat. No. 2,382,939 and U.S. Pat. No. 3,179,792, both teach a translucent glass or plastic sleeve for a standard fluorescent lamp/tube. However, all three of these patents teach that the phosphors are inside the lamp/tube envelope and none of those patents teach that the sleeve itself can be used as a means to convert or transform the primary UV radiation to another wavelength distribution of radiation.
U.S. Pat. No. 6,193,894 and the related U.S. Pat. No. 6,614,039, by inventor Brad Hollander, both teach sleeves made of UV C radiation transmitting fluoropolymers or silicone based materials (such as silicone polymers) that completely surround a low pressure mercury vapor lamp/tube to hermetically seal the lamp/tube. Neither patent makes reference to wavelength transforming materials with respect to the protective sleeve nor does either patent makes any reference to any UV radiation source other than a low pressure mercury vapor discharge tube.